6e27478c3d
This code had one purpose only, feed timing information into a test and was not used by anything else. The custom trace points unfortunatly were not accurate and this test was delivering informatin that conflicted with other tests we have due to placement of such trace points in the architecture and kernel code. For such measurements we are planning to use the tracing functionality in a special mode that would be used for metrics without polluting the architecture and kernel code with additional tracing and timing code. Furthermore, much of the assembly code used had issues. Signed-off-by: Anas Nashif <anas.nashif@intel.com> Signed-off-by: Daniel Leung <daniel.leung@intel.com>
76 lines
2.1 KiB
ArmAsm
76 lines
2.1 KiB
ArmAsm
/*
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* Copyright (c) 2016 Jean-Paul Etienne <fractalclone@gmail.com>
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*
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* SPDX-License-Identifier: Apache-2.0
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*/
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#include <toolchain.h>
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#include <linker/sections.h>
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#include <offsets_short.h>
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#include <arch/cpu.h>
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/* exports */
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GTEXT(arch_swap)
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GTEXT(z_thread_entry_wrapper)
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/* Use ABI name of registers for the sake of simplicity */
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/*
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* unsigned int arch_swap(unsigned int key)
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*
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* Always called with interrupts locked
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* key is stored in a0 register
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*/
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SECTION_FUNC(exception.other, arch_swap)
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/* Make a system call to perform context switch */
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ecall
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/*
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* when thread is rescheduled, unlock irq and return.
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* Restored register a0 contains IRQ lock state of thread.
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*
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* Prior to unlocking irq, load return value of
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* arch_swap to temp register t2 (from
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* _thread_offset_to_swap_return_value). Normally, it should be -EAGAIN,
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* unless someone has previously called arch_thread_return_value_set(..).
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*/
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la t0, _kernel
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/* Get pointer to _kernel.current */
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RV_OP_LOADREG t1, _kernel_offset_to_current(t0)
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/* Load return value of arch_swap function in temp register t2 */
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lw t2, _thread_offset_to_swap_return_value(t1)
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/*
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* Unlock irq, following IRQ lock state in a0 register.
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* Use atomic instruction csrrs to do so.
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*/
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andi a0, a0, MSTATUS_IEN
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csrrs t0, mstatus, a0
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/* Set value of return register a0 to value of register t2 */
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addi a0, t2, 0
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/* Return */
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jalr x0, ra
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/*
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* void z_thread_entry_wrapper(k_thread_entry_t, void *, void *, void *)
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*/
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SECTION_FUNC(TEXT, z_thread_entry_wrapper)
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/*
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* z_thread_entry_wrapper is called for every new thread upon the return
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* of arch_swap or ISR. Its address, as well as its input function
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* arguments thread_entry_t, void *, void *, void * are restored from
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* the thread stack (initialized via function _thread).
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* In this case, thread_entry_t, * void *, void * and void * are stored
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* in registers a0, a1, a2 and a3. These registers are used as arguments
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* to function z_thread_entry. Hence, just call z_thread_entry with
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* return address set to 0 to indicate a non-returning function call.
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*/
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jal x0, z_thread_entry
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